Theory

What is Size Exclusion/Gel Permeation Chromatography (SEC/GPC)?

Size exclusion or gel permeation chromatography (SEC/GPC) is a technique employed to separate complex mixtures of macromolecules according to their hydrodynamic size. This technique involves a mobile phase and a stationary phase comprised of a porous gel material. During separation, molecules having large hydrodynamic size exclude from the column initially while molecules have smaller hydrodynamic size are retained in the porous gel and elute later (Figure 2).



Schematic of the SEC/GPC separation process for a polymer sample containing component A and B

Figure 2.1 Scheme of the SEC/GPC separation process for a polymer sample containing component A and B.


After undergoing separation through the porous gel packed SEC/GPC columns, each separated fraction of the polymer flow through a series of detectors. The system configuration of an advanced detection SEC/GPC system is shown in Figure 2.2.



Schematic Depicting Advanced Detection SEC/GPC System Configuration

Figure 2. 2. Advanced detection SEC/GPC system configuration.


Depending on the detector arrangement/availability, molecular weight parameters can be determined by different calibration techniques.

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